1. Field of the Invention
This invention relates generally to robotics, and more particularly to robotic arms and systems for controlling such arms.
2. Description of the Related Art
Robotic arms—i.e., articulated mechanisms designed to perform one or more tasks, typically under the control of a computer—are commonly used in factory and assembly line environments. For example, one common task performed by a robotic arm is to grip a target object and then move it to a desired location. This is accomplished with the help of an ‘effector’ mechanism, typically located on the end of a robotic arm; a typical effector is a “gripper” which has at least one movable jaw that is closed in order to grip or grasp a target object.
Traditionally, angle sensors such as encoders are incorporated into a robotic arm's joints, and are used to determine the position of the arm. By knowing the exact length of each portion of the arm, and the size and angle of each joint, a computer can calculate the spatial position of the arm.
However, there are drawbacks associated with this method of operation. For example, the accuracy with which an arm can be positioned may be degraded as the mechanism's parts become worn. Positional accuracy requirements may also limit the speed with which the robotic arm can be manipulated, and require that a target object be precisely positioned prior to its being manipulated.